<template>
  <div id="home">
    <nav-bar class="home-nav"><div slot="center">购物街</div></nav-bar>
    <tab-control :titles="['流行', '新款', '精选']" 
                 @tabClick="tabClick"
                 ref="tabControl1"
                 class="tab-control"
                 v-show="isTabFixed"></tab-control>
    <scroll class="content" 
            ref = "scroll" 
            :probe-type="3" 
            @scroll="contentScroll" 
            :pull-up-load="true"
            @pullingUp="loadMore">
      <home-swiper :banners="banners" @swiperImageLoad="swiperImageLoad"></home-swiper>
      <recommend-view :recommends="recommends"></recommend-view>
      <feature-view></feature-view>
      <tab-control :titles="['流行', '新款', '精选']" 
                   @tabClick="tabClick"
                   ref="tabControl2"></tab-control>
      <good-list :goods="showGoods"></good-list>
    </scroll>

    <back-top @click.native = "backClick" v-show="isShowBackTop"></back-top>
  </div>
</template>

<script>
  import HomeSwiper from './childComps/HomeSwiper';
  import RecommendView from './childComps/RecommendView';
  import FeatureView from './childComps/FeatureView';

  import NavBar from 'components/common/navbar/NavBar';
  import TabControl from 'components/content/tabControl/TabControl';
  import GoodList from 'components/content/goods/GoodsList';
  // import GoodsListItem from 'components/content/goods/GoodsListItem';
  import Scroll from 'components/common/scroll/Scroll';
  
  import {getHomeMultidata, getHomeGoods} from "network/home";
  // import {debounce} from 'common/utils';
  import {itemListenerMixin, backTopMixin} from 'common/mixin'

  export default {
    name: "Home",
    components: {
      HomeSwiper,
      RecommendView,
      FeatureView,
      NavBar,
      TabControl,
      GoodList,
      Scroll,
    },
    mixins: [itemListenerMixin, backTopMixin],
    data() {
      return {
        banners: [],
        recommends: [],
        goods: {
          'pop': {page: 0, list: []},
          'new': {page: 0, list: []},
          'sell': {page: 0, list: []},
        },
        currentType: 'pop',
        tabOffsetTop: 0,
        isTabFixed: false,
        saveY: 0,
      }
    },
    computed: {
      showGoods() {
        return this.goods[this.currentType].list;
      }
    },
    destroyed() {
      console.log('home destoryed')
    },
    activated() {
      this.$refs.scroll.scrollTo(0, this.saveY, 0)
      this.$refs.scroll.refresh()
    },
    deactivated() {
      // 1.保存Y值
      this.saveY = this.$refs.scroll.getScrollY()
      
      // 2.取消全局事件的监听
      this.$bus.$off('itemImageLoad', this.itemImgListener)
    },
    created() {
      // 1. 请求多个数据
      this.getHomeMultidata();      

      // 2.请求商品数据
      this.getHomeGoods('pop');
      this.getHomeGoods('new');
      this.getHomeGoods('sell');
    },
    mounted() {
    },
    methods: {
      /**
       * 事件监听相关的方法
       */
      tabClick(index) {
        switch (index) {
          case 0: 
            this.currentType = 'pop';
            break;
          case 1:
            this.currentType = 'new';
            break;
          case 2:
            this.currentType = 'sell';
            break;
        }
        this.$refs.tabControl1.currentIndex = index;
        this.$refs.tabControl2.currentIndex = index;
      },
      contentScroll(position) {
        // 1.判断BackTop是否显示
        this.listenShowBackTop(position);

        // 2.决定tabControl是否吸顶(position: fixed)
        this.isTabFixed = (-position.y) > this.tabOffsetTop
      },
      loadMore() {
        this.getHomeGoods(this.currentType)
      },
      swiperImageLoad() {
        this.tabOffsetTop = this.$refs.tabControl2.$el.offsetTop;
      },
      /**
       * 网络请求相关的方法 
       */ 
      getHomeMultidata() {
        getHomeMultidata().then(res => {
        this.banners = res.data.banner.list;
        this.recommends = res.data.recommend.list
      })
      },
      getHomeGoods(type) {
        const page = this.goods[type].page + 1;
        getHomeGoods(type, page).then(res => {
          this.goods[type].list.push(...res.data.list);
          this.goods[type].page += 1;

          // 完成上拉加载更多
          this.$refs.scroll.finishPullUp()
      })
      }
    }
  }
</script>

<style scoped>
  #home {
    /* padding-top: 44px; */
    /* vh: viewport height 占比100%的视口 */
    height: 100vh;
    position: relative;
  }
  .home-nav {
    background-color: var(--color-tint);
    color: #fff;
    font-weight: 700;
    

    /* 在使用浏览器原生滚动时,为了让导航不跟随一起滚动 */
    /* position: fixed;
    left: 0;
    right: 0;
    top: 0;
    z-index: 9; */
  }


  .content {
    overflow: hidden;

    position: absolute;
    top: 44px;
    bottom: 49px;
    left: 0;
    right: 0;
  }

  .tab-control {
    position: relative;
    /* 以下这步跟老师不太一样,是为了解决滑动屏幕时nav-bar与control-bar之间的小缝隙 */
    margin-top: -0.5px;
    z-index: 9;
  }

  /* .content {
    height: calc(100% - 93px);
    overflow: hidden;
    margin-top: 44px;
  } */
</style>
